Next week's XML 2007 conference in Boston features speakers from all sides of the document format debate, including a document interop session with Miguel de Icaza (Novell) and Vijay Rajagopalan (Microsoft) that I expect will offer a lively discussion around Open XML, ODF, and XML-based interoperability in general.
My good friend and colleague Craig Kitterman has helped organize the event, and as you can see in the speaker list, they'll have many well-known presenters on XML technologies, standards, and related topics. If you're in the US Northeast or can get there next week, this conference is a great event for XML developers.
Since most Office Open XML related blogs do not mention it yet:
Windows Office Mobile 6.1 now supports Office Open XML
(About time since the iPhone already supported Office Open XML reading)